Past stock status and conservation advice
(From ISC10 Plenary Report)
After discussion of the ALBWG conclusions (Annex 9) and consideration of comments raised by Members, the Plenary offers no new conservation advice for North Pacific albacore above and beyond that which was provided at ISC9 in July 2009 (based on the advice of ISC7), pending the results of a new stock assessment, which is scheduled for 2011. That advice is:
“Previous scientific advice, based on the 2004 stock assessment, recommended that current fishing mortality rate (F) should not be increased. It was noted that management objectives for the IATTC and WCPFC are based on maintaining population levels which produce maximum sustainable yield. Due to updating, and improvements and refinements in data and models used in the 2006 stock assessment, it is now recognized that F2002-2004 (0.75) is high relative to most of the F reference points [commonly used in fisheries management] (see Table 5a in Annex 5) [of the ISC7 Plenary Report].
On the other hand, the same analysis indicates that the current  estimate of the SSB is the second highest in history but that keeping the current F would gradually reduce the SSB to the long-term average by the mid 2010s. Therefore, the recommendation of not increasing F from current level (F2002-2004=0.75) is still valid. However, with the projection based on the continued current high F, the fishing mortality rate will have to be reduced.”
Based on analyses conducted by the ALBWG since ISC9, the following points are highlighted:
- Both the ISC9 and ISC10 Plenaries note that there is increasing uncertainty concerning the status of North Pacific albacore in the absence of a new stock assessment.
- The ISC10 Plenary notes that there is no strong positive or negative signals in the age 6-9+ SSB index since the last stock assessment.
- The next stock assessment is expected to be completed in early 2011 and the results will be presented at ISC11.
- The ISC9 Plenary reported that the estimated value of FSSB-ATHL is 0.75yr-1 for a 25-year projection period using fishery data through 2008. This value is similar to F2002-2004 = 0.75 yr-1, estimated in the last stock assessment.
Pacific Bluefin Tuna
Given the conclusions of the July 2010 PBFWG workshop (Annex 7), the current (2004 - 2006) level of F relative to potential biological reference points, and the increasing trend of F, it is important that the level of F is decreased below the 2002-2004 levels, particularly on juvenile age classes.
While further guidance from the management authority is necessary, including guidance on reference points and the desirable degree of reduction, the fishing mortality rate of striped marlin (which can be converted into effort or catch in management) should be reduced from the current level (2001-2003), taking into consideration various factors associated with this species and its fishery. Until appropriate measures in this regard are taken, the fishing mortality rate should not be increased.
The WCPO and EPO stocks of swordfish are healthy and above the level required to sustain recent catches.